The patch titled mempolicy: clean-up mpol-to-str() mempolicy formatting has been added to the -mm tree. Its filename is mempolicy-clean-up-mpol-to-str-mempolicy-formatting.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: mempolicy: clean-up mpol-to-str() mempolicy formatting From: Lee Schermerhorn <lee.schermerhorn@xxxxxx> mpol-to-str() formats memory policies into printable strings. Currently this is only used to display "numa_maps". A subsequent patch will use mpol_to_str() for formatting tmpfs [shmem] mpol mount options, allowing us to remove essentially duplicate code in mm/shmem.c. This patch cleans up mpol_to_str() generally and in preparation for that patch. 1) show_numa_maps() is not checking the return code from mpol_to_str(). There's not a lot we can do in this context if mpol_to_str() did return the error [insufficient space in buffer]. Proposed "solution": just check, under DEBUG_VM, that callers are providing sufficient buffer space for the policy, flags, and a few nodes. This way, we'll get some display. show_numa_maps() is providing a 50-byte buffer, so it won't trip this check. 50-bytes should be sufficient unless one has a large number of nodes in a very sparse nodemask. 2) The display of the new mode flags ["static" & "relative"] was set up to display multiple flags, separated by a "bar" '|'. However, this support is incomplete--e.g., need_bar was never incremented; and currently, these two flags are mutually exclusive. So remove the "bar" support, for now, and only display one flag. 3) Use snprint() to format flags, so as not to overflow the buffer. Not that it's ever happed, AFAIK. Signed-off-by: Lee Schermerhorn <lee.schermerhorn@xxxxxx> Cc: Christoph Lameter <clameter@xxxxxxx> Cc: David Rientjes <rientjes@xxxxxxxxxx> Cc: Mel Gorman <mel@xxxxxxxxx> Cc: Andi Kleen <ak@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/mempolicy.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) diff -puN mm/mempolicy.c~mempolicy-clean-up-mpol-to-str-mempolicy-formatting mm/mempolicy.c --- a/mm/mempolicy.c~mempolicy-clean-up-mpol-to-str-mempolicy-formatting +++ a/mm/mempolicy.c @@ -1966,6 +1966,11 @@ static inline int mpol_to_str(char *buff unsigned short mode; unsigned short flags = pol ? pol->flags : 0; + /* + * Sanity check: room for longest mode, flag and some nodes + */ + VM_BUG_ON(maxlen < strlen("interleave") + strlen("relative") + 16); + if (!pol || pol == &default_policy) mode = MPOL_DEFAULT; else @@ -1992,7 +1997,6 @@ static inline int mpol_to_str(char *buff default: BUG(); - return -EFAULT; } l = strlen(policy_types[mode]); @@ -2003,16 +2007,17 @@ static inline int mpol_to_str(char *buff p += l; if (flags) { - int need_bar = 0; - if (buffer + maxlen < p + 2) return -ENOSPC; *p++ = '='; + /* + * Currently, the only defined flags are mutually exclusive + */ if (flags & MPOL_F_STATIC_NODES) - p += sprintf(p, "%sstatic", need_bar++ ? "|" : ""); - if (flags & MPOL_F_RELATIVE_NODES) - p += sprintf(p, "%srelative", need_bar++ ? "|" : ""); + p += snprintf(p, buffer + maxlen - p, "static"); + else if (flags & MPOL_F_RELATIVE_NODES) + p += snprintf(p, buffer + maxlen - p, "relative"); } if (!nodes_empty(nodes)) { _ Patches currently in -mm which might be from lee.schermerhorn@xxxxxx are mm-use-zonelists-instead-of-zones-when-direct-reclaiming-pages.patch mm-introduce-node_zonelist-for-accessing-the-zonelist-for-a-gfp-mask.patch mm-remember-what-the-preferred-zone-is-for-zone_statistics.patch mm-use-two-zonelist-that-are-filtered-by-gfp-mask.patch mm-have-zonelist-contains-structs-with-both-a-zone-pointer-and-zone_idx.patch mm-have-zonelist-contains-structs-with-both-a-zone-pointer-and-zone_idx-fix-memcg-ooms.patch mm-have-zonelist-contains-structs-with-both-a-zone-pointer-and-zone_idx-just-return-do_try_to_free_pages.patch mm-have-zonelist-contains-structs-with-both-a-zone-pointer-and-zone_idx-just-return-do_try_to_free_pages-do_try_to_free_pages-gfp_mask-redundant.patch mm-filter-based-on-a-nodemask-as-well-as-a-gfp_mask.patch mm-filter-based-on-a-nodemask-as-well-as-a-gfp_mask-doc-fixes.patch mm-filter-based-on-a-nodemask-as-well-as-a-gfp_mask-make-dequeue_huge_page_vma-obey-mpol_bind-nodemask.patch mm-filter-based-on-a-nodemask-as-well-as-a-gfp_mask-make-dequeue_huge_page_vma-obey-mpol_bind-nodemask-rework.patch mm-filter-based-on-a-nodemask-as-well-as-a-gfp_mask-deporkify.patch mempolicy-add-bitmap_onto-and-bitmap_fold-operations.patch mempolicy-create-mempolicy_operations-structure-fix.patch mempolicy-disallow-static-or-relative-flags-for-local-preferred-mode.patch mempolicy-fix-parsing-of-tmpfs-mpol-mount-option.patch mempolicy-rename-mpol_free-to-mpol_put.patch mempolicy-rename-mpol_copy-to-mpol_dup.patch mempolicy-write-lock-mmap_sem-while-changing-task-mempolicy.patch mempolicy-fixup-fallback-for-default-shmem-policy.patch mempolicy-rename-struct-mempolicy-policy-member-to-mode.patch mempolicy-mark-shared-policies-for-unref.patch mempolicy-document-setget_policy-vm_ops-apis.patch mempolicy-rework-mempolicy-reference-counting.patch mempolicy-use-mpol_preferred-for-system-wide-default-policy.patch mempolicy-mpol_preferred-cleanups-for-local-allocation.patch mempolicy-use-mpol_f_local-to-indicate-preferred-local-policy.patch mempolicy-clean-up-mpol-to-str-mempolicy-formatting.patch mempolicy-rework-shmem-mpol-parsing-and-display.patch mempolicy-support-mpol=local-tmpfs-mount-option.patch mempolicy-use-struct-mempolicy-pointer-in-shmem_sb_info.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html